Is it permissible to say: "By the life of Allah," or "By the life of Muhammad," or "O Muhammad"?

Question:
He says: Honorable Shaykh, may Allah grant you success. I went to an Arab country, and I found that its people say things, among which is that if one of them is surprised by something, he says "O Muhammad," and if one of them wants something, he says "By the life of Allah," or "By the life of the Qur'an," or "By the life of Muhammad." Are these phrases correct? The life of Allah is correct; this is a category of one of the attributes of Allah (Mighty and Majestic), and it is the life of Allah.

Answer:
As for the life of Muhammad, or the life of so-and-so, that is shirk (associating partners with Allah). It is not permissible to swear by a created being. Swearing by a created being is not permissible. And saying "O Muhammad" is shirk. This is calling for aid and a cry to the Messenger (peace and blessings be upon him). It is obligatory for the student of knowledge to teach the people, to make things clear to them, and to spread the correct creed. He should not leave the people as they are. Rather, he should clarify things for the people. Yes.